Gonadotrophin-releasing hormone (GnRH) is produced from cells in the hypothalamus. It is then released into small blood vessels that carry the hormone to the pituitary gland. As a consequence, the pituitary gland produces luteinizing hormone (LH) and follicle-stimulating (FSH) hormones. These hormones, LH and FSH, are essential to male and female reproductive health.
GnRH causes the pituitary gland to secrete LH and FSH. In childhood, GnRH levels are low. As puberty begins, GnRH levels start to rise. When the testes and ovaries are fully developed, GnRH, LH, and FSH production are controlled by the levels of testosterone and female sex hormones (estrogen and progesterone). In women, FSH encourages eggs to grow in the ovaries. Leadning to the production of estrogen, which signals to the pituitary gland to decrease the release of FSH and to produce more LH, causing ovulation and FSH and LH levels to drop. In men, GnRH stimulates the production of LH from the pituitary gland. LH attaches to receptor cells in the testes, which starts the production of sperm cells.
Research is still being conducted on the effects of having too much GnRH. In rare cases, pituitary tumors can develop, which increases the production of gonadotropins (LH and FSH), which might cause the body to overproduce testosterone and estrogen. If GnRH levels are too low, it often means that a person does not begin puberty. Kallmann’s Syndrome is an condition where gonadotropin levels are low due to inadequate GnRH levels. This condition is more common among men and is accompanied by a decreased sense of smell. Also, damage to the hypothalamus can halt GnRH production. This will also stop the regular production of FSH and LH. This may lead to amenorrhea in women, loss of sperm production in men, and loss of hormones made from the ovaries or testes.
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